Someone asked how often you check boxes.... My personal feeling is once you have an established nest I don't check that box until 30 days have passed. I will check any other boxes that do not have an active nest to deal with predation and unwanted visitors about every one to two weeks. All you are doing IMHO if you check them more often is molesting the hen and kicking her off the nest which she needs to be on and potentially having her leave the nest for an indeterminate time. I can't see the benefit in doing that at all just to satisfy your own curiosity. To check for a successful nesting finding the egg membranes IMHO is the best way to determine a hatched egg. They are the leathery crumpled membrane that was inside the egg prior to hatching and is left behind along with the egg fragments. Egg fragments alone might have different meanings which includes predation.